Is the mirrored blades glyph bugged?

It was my first time using it yesterday and I was pvping I got feared and a chaos bolt was upon me so I broke out the fear and deterranced the lock was at like 40% health and I reflected the spell back and it hit him for 201K it was on AB. Im asking if it was bugged because it hit him so hard back he ending up killing his self with his own spell. Is that normal for spells to crit while being reflected?